A defendant in a trademark infringement case could assert it made “fair use” of a descriptive term without having to disprove any consumer confusion resulting from that use, the U.S. Supreme Court has ruled.

“It takes a long stretch to claim that defense of fair use entails any burden to negate confusion,” wrote Justice David Souter for a unanimous court. Souter added that “some possibility of consumer confusion must be compatible with fair use.”

(KP Permanent Make-Up, Inc. v. Lasting Impression I, Inc. Docket No. 03-409. Click here to read full opinion.)

The fair-use doctrine lets competing companies use trademarked terms for descriptive purposes.

The court’s opinion clarifies parties’ respective burdens of proof in trademark disputes over descriptive terms. Federal appeals courts were split on the obligation of a party asserting the fair-use defense against a trademark infringement claim to prove its use is unlikely cause consumer confusion.

The case involves Lasting Impression I, Inc. of Englewood, N.J., a maker of liquid pigments that permanently change skin color to cover up scars and mask pigmentation disorders. The company sells its product under the trademarked name of Micro Colors.

A competitor, California-based KP Permanent Make-Up, Inc., used the word “microcolors” on product bottles and marketing fliers, which prompted Lasting Impressions to demand that KP stop using the term.

KP in response filed a declaratory judgment action, arguing its use of the term microcolors predated Lasting Impression’s trademark registration in 1993. It also argued that the term was widely used in the industry, and that the trademark only protected a Micro Colors logo, not the term itself.

Lasting Impression counterclaimed for trademark infringement.

A trial court judge granted KP summary judgment on the infringement claim, concluding it was making fair use of the descriptive term microcolors. However, the 9th U.S. Circuit Court of Appeals reversed the decision, ruling that the trial judge failed to consider the issue of possible consumer confusion about the origin of KP’s products.

Souter rejected the 9th Circuit’s rationale. A defendant, Souter wrote, only has to persuade a fact finder that a plaintiff has not carried its burden of proof in making out a prima facie case of infringement, which includes likelihood of confusion.

The Supreme Court’s ruling amplifies the perils of using descriptive trademarks, according to trademark law expert Douglas R. Wolf of Wolf Greenfield in Boston.

“It’s easier to prove infringement when a strong mark is used, such as Apple with computers. They are arbitrary and fanciful and have no meaning apart from the product.”

However, companies often opt for a descriptive mark because its easier to brand and sell a product when consumers can immediately understand what a product is about, Wolf said, which often pits marketing departments against in-house lawyers and their outside counsel.

“This case gives ammunition to the legal argument for staying away from descriptive marks,” Wolf said.